Marcro micro econmiy david begg chapter 029

Chapter 029. Disorders of the Eye (Part 12) ppt

Chapter 029. Disorders of the Eye (Part 12) ppt
... people of northern European descent Their diagnosis is obvious when they are visible as glittering particles upon the surface of the optic disc However, in many patients they are hidden beneath the ... fulminant papilledema Optic Disc Drusen These are refractile deposits within the substance of the optic nerve head (Fig 29-13) They are unrelated to drusen of the retina, which occur in age-related ... insidious fashion while the optic nerve develops atrophy In this setting, reduction of optic disc swelling is an ominous sign of a dying nerve rather than an encouraging indication of resolving papilledema...
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Chapter 029. Disorders of the Eye (Part 14) pps

Chapter 029. Disorders of the Eye (Part 14) pps
... viewing light reflected from the fundus with an ophthalmoscope or by examining the dilated eye using the slit lamp The only treatment for cataract is surgical extraction of the opacified lens Over ... with chronic elevation of intraocular pressure In Americans of African descent it is the leading cause of blindness The mechanism whereby raised intraocular pressure injures the optic nerve is not ... In our litigious society, the fraudulent pursuit of recompense has spawned an epidemic of factitious visual loss Chronic Visual Loss Cataract This is a clouding of the lens sufficient to reduce...
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Chapter 029. Disorders of the Eye (Part 15) pdf

Chapter 029. Disorders of the Eye (Part 15) pdf
... vessels from the choroid grow through defects in Bruch's membrane into the potential space beneath the retinal pigment epithelium Leakage from these vessels produces elevation of the retina and ... complement pathway The nonexudative process begins with the accumulation of extracellular deposits, called drusen, underneath the retinal pigment epithelium On ophthalmoscopy, they are pleomorphic ... pressure by reducing aqueous production Laser treatment of the trabecular meshwork in the anterior chamber angle improves aqueous outflow from the eye If medical or laser treatments fail to halt optic...
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Chapter 029. Disorders of the Eye (Part 16) pps

Chapter 029. Disorders of the Eye (Part 16) pps
... by administration of panretinal laser photocoagulation at the appropriate point in the evolution of the disease For further discussion of the manifestations and management of diabetic retinopathy, ... pigmentosa with black clumps of pigment in the retinal periphery known as "bone spicules." There is also atrophy of the retinal pigment epithelium, making the vasculature of the choroid easily visible ... deposits of clumped pigment in the peripheral retina, called bone spicules because of their vague resemblance to the spicules of cancellous bone, give the disease its name (Fig 29-17) The name...
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Chapter 029. Disorders of the Eye (Part 17) potx

Chapter 029. Disorders of the Eye (Part 17) potx
... the appearance of enophthalmos True enophthalmos occurs commonly after trauma, from atrophy of retrobulbar fat, or fracture of the orbital floor The position of the eyes within the orbits is measured ... be considered if the cause remains unknown after careful review of the history and thorough examination of the eye Figure 29-18 Proptosis When the globes appear asymmetric, the clinician must ... decide which eye is abnormal Is one eye recessed within the orbit (enophthalmos) or is the other eye protuberant (exophthalmos, or proptosis)? A small globe or a Horner's syndrome can give the appearance...
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Chapter 029. Disorders of the Eye (Part 18) ppt

Chapter 029. Disorders of the Eye (Part 18) ppt
... limitation of motility The width of the palpebral fissures is measured in primary gaze to quantitate the degree of ptosis The ptosis will be underestimated if the patient compensates by lifting the ... drooping of the eyelid Unilateral or bilateral ptosis can be congenital, from dysgenesis of the levator palpebrae superioris, or from abnormal insertion of its aponeurosis into the eyelid Acquired ... dehiscence or stretching of the aponeurotic tendon, which connects the levator muscle to the tarsal plate of the eyelid It occurs commonly in older patients, presumably from loss of connective tissue...
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Chapter 029. Disorders of the Eye (Part 19) ppsx

Chapter 029. Disorders of the Eye (Part 19) ppsx
... affecting the innervation to either of the two muscles that open the eyelid: Müller's muscle or the levator palpebrae superioris Examination of the pupil helps to distinguish between these two ... syndrome, the eye with ptosis has a smaller pupil and the eye movements are full In an oculomotor nerve palsy, the eye with the ptosis has a larger, or a normal, pupil If the pupil is normal but there ... ptosis with normal eye movements and pupils Double Vision (Diplopia) The first point to clarify is whether diplopia persists in either eye after covering the opposite eye If it does, the diagnosis...
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Chapter 029. Disorders of the Eye (Part 20) ppt

Chapter 029. Disorders of the Eye (Part 20) ppt
... compression (tumor, aneurysm) Miswiring of sprouting fibers to the levator muscle and the rectus muscles results in elevation of the eyelid upon downgaze or adduction The pupil also constricts upon attempted ... itself There is bilateral ptosis because the levator muscle is innervated by a single central subnucleus There is also weakness of the contralateral superior rectus, because it is supplied by the ... space the oculomotor nerve is vulnerable to aneurysm, meningitis, tumor, infarction, and compression In cerebral herniation the nerve becomes trapped between the edge of the tentorium and the uncus...
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Chapter 029. Disorders of the Eye (Part 21) pps

Chapter 029. Disorders of the Eye (Part 21) pps
... generation of saccades to the contralateral side After hemispheric stroke, the eyes usually deviate towards the lesioned side because of the unopposed action of the frontal eye field in the normal ... Seizures generally have the opposite effect: the eyes deviate conjugately away from the irritative focus Parietal lesions disrupt smooth pursuit of targets moving toward the side of the lesion Bilateral ... multiple sclerosis are the most common etiologies of brainstem abducens palsy After leaving the ventral pons, the abducens nerve runs forward along the clivus to pierce the dura at the petrous apex,...
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Chapter 029. Disorders of the Eye (Part 22) ppsx

Chapter 029. Disorders of the Eye (Part 22) ppsx
... a combined lesion of the medial longitudinal fasciculus and the abducens nucleus on the same side The patient's only horizontal eye movement is abduction of the eye on the other side Figure 29-19 ... position of gaze the eyes appear normal B Horizontal gaze to the left is intact C On attempted horizontal gaze to the right, the left eye fails to adduct In mildly affected patients the eye may ... controlled at the level of the midbrain The neuronal circuits affected in disorders of vertical gaze are not fully elucidated, but lesions of the rostral interstitial nucleus of the medial longitudinal...
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Chapter 029. Disorders of the Eye (Part 23) pptx

Chapter 029. Disorders of the Eye (Part 23) pptx
... examination of the eyes Observation of nystagmoid movements of the optic disc on ophthalmoscopy is a sensitive way to detect subtle nystagmus Gaze-Evoked Nystagmus This is the most common form of jerk ... the eyes are held eccentrically in the orbits, they have a natural tendency to drift back to primary position The subject compensates by making a corrective saccade to maintain the deviated eye ... Kanski JJ: Systemic Diseases and the Eye St Louis, Mosby, 2001 Leibowitz HM: The red eye N Engl J Med 343:345, 2000 [PMID: 10922425] Leigh RJ, Zee DS: The Neurology of Eye Movements, 4th ed Oxford,...
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Chapter 029. Disorders of the Eye (Part 8) ppsx

Chapter 029. Disorders of the Eye (Part 8) ppsx
... cause of a red, painful eye Susceptible eyes have a shallow anterior chamber, either because the eye has a short axial length (hyperopia) or a lens enlarged by the gradual development of cataract ... judicious use of topical glucocorticoids Dilation of the pupil reduces pain and prevents the formation of synechiae Posterior Uveitis This is diagnosed by observing inflammation of the vitreous, ... disease Some patients have panuveitis, or inflammation of both the anterior and posterior segments of the eye Posterior uveitis is a manifestation of autoimmune diseases such as sarcoidosis, Behçet's...
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Chapter 029. Disorders of the Eye (Part 9) potx

Chapter 029. Disorders of the Eye (Part 9) potx
... Ophthalmoscopy reveals zones of whitened, edematous retina following the distribution of branch retinal arterioles Complete occlusion of the central retinal artery produces arrest of blood flow and a ... term refers to a transient ischemic attack of the retina (Chap 364) Because neural tissue has a high rate of metabolism, interruption of blood flow to the retina for more than a few seconds results ... (Fig 29-6) Emboli are composed of either cholesterol (Hollenhorst plaque), calcium, or platelet-fibrin debris The most common source is an atherosclerotic plaque in the carotid artery or aorta,...
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Chapter 029. Disorders of the Eye (Part 10) potx

Chapter 029. Disorders of the Eye (Part 10) potx
... confirm the diagnosis Glucocorticoids should be started immediately, without waiting for the biopsy to be completed The diagnosis of arteritic AION is difficult to sustain in the face of a negative ... glucocorticoids can be instituted immediately to prevent blindness in the second eye Symptoms of polymyalgia rheumatica may be present; the sedimentation rate and C-reactive protein level are usually ... spontaneously, while others evolve a frank obstruction with extensive retinal bleeding ("blood and thunder" appearance), infarction, and visual loss Venous occlusion of the retina is often idiopathic,...
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Chapter 029. Disorders of the Eye (Part 11) potx

Chapter 029. Disorders of the Eye (Part 11) potx
... gradual, painless, severe, central visual loss in one eye, followed weeks or months later by the same process in the other eye Acutely, the optic disc appears mildly plethoric with surface capillary ... (Fig 29 -11) without a phase of acute optic disc edema Many agents have been implicated as a cause of toxic optic neuropathy, but the evidence supporting the association for many is weak The following ... (measured months after the attack), but the recovery of visual function occurs more rapidly For some patients, optic neuritis remains an isolated event However, the ONTT showed that the 10-year cumulative...
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